My girlfriend says I'm powered by vegan magic because I'm always full of beans(no pun intended) and never get ill
"Beans, beans, the Magick Fruit, the more you eat 'em, the more you toot!"
Seriously though, have you considered that it may be your training routine and not your diet? If you are doing the same routine for a while (my case is usually about 2 mos) your body will adapt and you'll hit a sticking point. And if you aren't progressively loading (increasing volume or weight) during each workout then you aren't progressing, period. You have to change something up which can be many things; training frequency, reps, sets, lifting (and lowering) speed, rest time between sets, etc.
For myself all I do is change rep ranges. I'll do 12-15 reps for a while, 8-10 reps, and at that point my muscles are needing a huge kick in the pants so I go down to reps for strength at 3-5. After that I take a couple weeks off and go back into the high reps.
I learned this little trick doing HST. Google it if interested. Not many people are because there is a HUGE amount of science behind it and its not the most "mainstream" of programs which is intimidating. For myself, the geek in me fell in love!
For now, I'm doing my own compromise which again is what I posted above. I may go back to doing strictly HST in the future though. Will see if my joints and endurance levels can hold up to it.